1999 Toyota Sienna Noise when turning to the right only

I am having a simular problem on my 2001 Sienna, also when it is cold. The power steering pump makes a noise when it is cold out. After the vehicle warms up the noise stops. During warm days it works fine. It usually make this noise when the temp drops below about 40 degrees out side. No noise when temp is warmer outside. Has now began being harder to turn while still making noise. I usually just let the vehicle warm up a few minutes, it then works fine. Have looked the price of a rebuilt power steering pump, it is over $200.00. Hopefully someone has a cheaper solution. Have changed the fluid in the pump, but the noise and ruffness is still there. New belt was also installed, noise and ruffness continues.